Pharmaceutics

Master answer

Enantiomers

• Molecules which have the same bond structure but are mirror images of each other.
• These molecules rotate light in opposite directions:
  • (S)-(+)-naproxen is used to treat arthritis pain
  • (R)-(–)-naproxen causes liver poisoning with no analgesic effect.
  • (S)-(+)-warfarin, metabolised by CYP2C9, 3-5 times more potent
  • (R)-(–)-warfarin, metabolised by CYP2C19, CYP1A2, CYP3A4
• These are isomers which share pharmachemical properties (boiling point, density…) and chemical formula but different 3-D structural arrangement.
• If action depends on pharacochemical properties then it is shared between enantomes
• If action depends on binding to specific sites then it can be markedly different between enantomers.

Enantomers are a subclass of Sterioisomers which are molecules with the same bond structure, different 3D arrangement. 

• Sterioisomers have a singel chiral center and can be either:
  • Geometric
  • Optical or enantomeric
• Diastereoisomers have more than one chiral center and can be either:
  • Geometric
  • Optical non-enantomeric

Gladwin 2016

Answer by Gladwin